Modeling Interdependent and Periodic Real-World Action Sequences

Mobile health applications, including those that track activities such as exercise, sleep, and diet, are becoming widely used. Accurately predicting human actions is essential for targeted recommendations that could improve our health and for personalization of these applications. However, making such predictions is extremely difficult due to the complexities of human behavior, which consists of a large number of potential actions that vary over time, depend on each other, and are periodic. Previous work has not jointly modeled these dynamics and has largely focused on item consumption patterns instead of broader types of behaviors such as eating, commuting or exercising. In this work, we develop a novel statistical model for Time-varying, Interdependent, and Periodic Action Sequences. Our approach is based on personalized, multivariate temporal point processes that model time-varying action propensities through a mixture of Gaussian intensities. Our model captures short-term and long-term periodic interdependencies between actions through Hawkes process-based self-excitations. We evaluate our approach on two activity logging datasets comprising 12 million actions taken by 20 thousand users over 17 months. We demonstrate that our approach allows us to make successful predictions of future user actions and their timing. Specifically, our model improves predictions of actions, and their timing, over existing methods across multiple datasets by up to 156%, and up to 37%, respectively. Performance improvements are particularly large for relatively rare and periodic actions such as walking and biking, improving over baselines by up to 256%. This demonstrates that explicit modeling of dependencies and periodicities in real-world behavior enables successful predictions of future actions, with implications for modeling human behavior, app personalization, and targeting of health interventions.Comment: Accepted at WWW 201

Capture of Mediterranean Fruit Flies and Melon Flies (Diptera: Tephritidae) in Food-Baited Traps in Hawaii

Food-based attractants are an important component of tephritid fruit fly detection programs, because they are general baits that are neither sex- nor species-specific. Two widely used food baits are enzymatic hydrolyzed torula yeast, which is presented as an aqueous solution that also serves to catch insects (wet trap), and a synthetic lure that combines ammomonium acetate, putrescine, and trimethylamine and may be presented with or without a water-based catch system. Recently, the liquid attractant CeraTrap, which is an enzymatic hydrolyzed animal protein, has been shown to be equally or more effective than traditional protein baits in capturing species of Anastrepha. The present study compares capture of wild Mediterranean fruit flies, Ceratitis capitata (Wiedemann), and melon flies, Zeugodacus cucurbitae (Coquillett) in traps baited with torula yeast or CeraTrap. In addition, one sampling interval compared the catch of C. capitata in wet traps baited with torula yeast, a synthetic food lure, or CeraTrap. CeraTrap was generally more effective in capturing both sexes of C. capitata than the other food baits, while torula yeast resulted in higher captures of Z. cucurbitae than CeraTrap. Results are compared with other trapping studies of tephritids involving food-based attractants

Brillouin spectral deconvolution method for centimeter spatial resolution and high-accuracy strain measurement in Brillouin sensors

This paper was published in Optics Letters and is made available as an electronic reprint with the permission of OSA. The paper can be found at the following URL on the OSA website: http://www.opticsinfobase.org/abstract.cfm?URI=ol-30-7-705. Systematic or multiple reproduction or distribution to multiple locations via electronic or other means is prohibited and is subject to penalties under law.Shahraam Afshar V., Xiaoyi Bao, Lufan Zou, and Liang Che

Analytically Tractable Models for Decision Making under Present Bias

Time-inconsistency is a characteristic of human behavior in which people plan for long-term benefits but take actions that differ from the plan due to conflicts with short-term benefits. Such time-inconsistent behavior is believed to be caused by present bias, a tendency to overestimate immediate rewards and underestimate future rewards. It is essential in behavioral economics to investigate the relationship between present bias and time-inconsistency. In this paper, we propose a model for analyzing agent behavior with present bias in tasks to make progress toward a goal over a specific period. Unlike previous models, the state sequence of the agent can be described analytically in our model. Based on this property, we analyze three crucial problems related to agents under present bias: task abandonment, optimal goal setting, and optimal reward scheduling. Extensive analysis reveals how present bias affects the condition under which task abandonment occurs and optimal intervention strategies. Our findings are meaningful for preventing task abandonment and intervening through incentives in the real world

Capturing Males of Pestiferous Fruit Flies (Diptera: Tephritidae): Is the Combination of Triple-Lure Wafers and Insecticidal Strips as Effective as Standard Treatments?

The detection of invasive tephritid fruit fly pests relies primarily on traps baited with male-specific lures. Three different male lures are typically used, and accordingly three sets of traps are deployed: those baited with liquid methyl eugenol (ME) or liquid cue lure (CL) for different Bactrocera species and those baited with plug-bearing trimedlure (TML) for Ceratitis species. The liquid lures contain the insecticide naled, whereas the trimedlure plugs contain no toxicant. Preparing the liquid solutions and servicing three types of traps requires consid- erable labor, and handling naled (and possibly ME) introduces potential health risks. The purpose of this study was to compare the effectiveness of Jackson traps baited with a solid dispenser (wafer) containing all three male lures plus a separate insecticidal (DDVP; 2, 2-dichlorovinyl dimethyl phosphate) strip with Jackson traps baited with the standard male lure/toxicant combinations. Trapping was conducted during two 12-week periods in a coffee field on Oahu, Hawaii. The effectiveness of the wafer-baited traps varied among different species. Catch of Bactrocera dorsalis (Hendel) males was similar between wafer-baited and liquid ME-baited traps for both sampling periods. Conversely, traps baited with the standard TML plug captured significantly more Ceratitis capitata (Wiedemann) males than the wafer-baited traps in both sampling periods. The relative effectiveness of the two trap treatments varied between sampling periods for Bactrocera cucurbitae (Coquillett) males. Based on these results, the triple-lure wafer plus separate kill strip does not, at present, appear to be a viable substitute for the male lure/toxicant combinations currently in use

Testing the Temporal Limits of Lures and Toxicants for Trapping Fruit Flies (Diptera: Tephritidae): Additional Weathering Studies of Solid Bactrocera and Zeugodacus Male Lures and Associated Insecticidal Strips

Detection of pestiferous fruit flies (Diptera: Tephritidae) relies largely on traps baited with male-specific attractants. Surveillance programs in Florida and California use liquid methyl eugenol (ME, attractive to males of Bactrocera dorsalis (Hendel)) and liquid cue-lure (CL, attractive to males of Zeugodacus cucurbitae (Coquillett)) mixed with the toxicant naled to bait detection traps. However, this practice requires considerable time and may subject personnel to health risks. Recent work indicates that solid male lures deployed with a separate insecticidal (DDVP) strip are as effective as the standard liquid formulations. Specifically, solid ME and CL dispensers and DDVP strips were weathered for 6 or 12 weeks under summer conditions in AZ and FL and subsequently field tested in Hawaii. Results showed that (i) solid ME dispensers weathered for 6 weeks, but not 12 weeks, were as attractive as fresh liquid ME, and (ii) solid CL dispensers and the insecticidal strips were as effective as fresh liquid formulation for at least 12 weeks. The present study expands upon these earlier findings and addresses two specific questions: Could solid ME dispensers be deployed for 8 or 10 weeks without loss of effectiveness? Could solid CL dispensers and insecticidal strips be deployed for intervals even longer than 12 weeks? Adopting the same protocol noted above, the present study indicates that effective field longevities are 10 weeks for solid ME dispensers, at least 20 weeks for solid CL dispensers, and 12 weeks for the DDVP strips. Comparisons are drawn with related studies, and implications for tephritid surveillance programs are discussed

EFFECT OF THUMB ABDUCTION AND ADDUCTION ON HYDRODYAMIC CHARACTERISTICS OF A MODEL OF THE HUMAN HAND

The purpose of this study was to compare hydrodynamic characteristics of human hand models with the thumb abducted and the thumb adducted using pressure differential and flow visualization techniques. Two different models of an adult man's right hand (Model A, the hand with abducted thumb; Model B, the hand with thumb adducted) were made with polyester resin. The magnitudes of pressure acting on holes located at the hand model surfaces were measured for various pitch angles to a flow of air in a wind tunnel. Flow visualization of air around the model was conducted using a laser beam. By means of the pressure data, the magnitudes of fluid force were calculated. The experimental results revealed that the thumb position has a large influence on the pressure distribution. The difference of the pressure distribution affected the hydrodynamic characteristics